Wercker

This PR has the wercker file that determines which box the app gets built on and handles installing the php mongo extension.  Normally I'd update the box itself and install the mongo extension there, but since this is the only app that needs mongo, it seems to make more sense to only install it here rather than make the build process longer for other apps.

The PR also includes the Capistrano scripts to push the updated code to the servers.

@jonuy